WO1999010834A1

WO1999010834A1 - A method and apparatus for handwriting capture, storage, and ind exing

Info

Publication number: WO1999010834A1
Application number: PCT/US1998/017460
Authority: WO
Inventors: Kankanahalli Srinivas; Vasudevan Jagannathan; Sunitra Mitra Reddy; Yenumula Venkataramana Reddy; Raghu Ram Karinthi; Kurishinkal Joseph Cleetus
Original assignee: Cybermarche, Inc.
Priority date: 1997-08-27
Filing date: 1998-08-21
Publication date: 1999-03-04
Also published as: WO1999010834A9; AU9115498A

Abstract

A handwriting capture and storage device (HCSD) comprises a digitizer (170) for generating X, Y coordinates corresponding to movement of a pen on a digitizer surface. A micro-controller (121) stores the X, Y coordinate data in a compressed format in a randomly accessible permanent storage (123). The X, Y coordinate data is provided later to a digital processing system for further processing to perform functions such as character recognition. An HCSD need not perform character recognition function, the device can be implemented to consume minimal power and space. The present invention further provides a flexible indexing scheme which enables a user to organize information written as multiple pages. The indexing scheme allows data to be added into pre-existing pages without having to copy the whole page to a new place in the non-volatile memory.

Description

A METHOD AND APPARATUS FOR HANDWRITING CAPTURE, STORAGE, AND INDEXING

Background of the Invention

Field of the Invention The present invention relates generally to the field of electronic handwriting capture devices, and more specifically to a method and apparatus for capturing, storing and indexing data representative of a pattern wπtten by a user, and later enable an external device to recognize the characters represented by the stored data.

Related Art Wπting on a sheet of paper with a pen or pencil is a common method of recording information

While writing on a paper may be common, the resulting wπtings may not be well-suited for further processing. For example, a search for a particular piece of information stored on a large volume of papers may require manually going through each paper, consuming a lot of time and labor.

Hence, wπtings may be subsequently scanned into a computer system for electronically processing the information wπtten. For example, one may scan a pattern wπtten on a paper into a computer system. As is well appreciated in the art, electronically stored information lends well to further processing. A search for a particular piece of information, even m a large volume of data, may consume very little time.

To integrate such a scanning step with a wntmg step, devices are known m the art which simultaneously capture writings in an electronic format while a user wπtes. For example, a Personal

Digital Assistant (such as Newton from Apple Corporation and EO from AT&T) may provide a display screen on which a user may wπte. As a user wπtes on the display screen using a pen, a personal digital assistant (PDA) performs functions such as character recognition to map the pattern wπtten into a set of characters according to the movement of the pen on the display screen. The PDA may display and/or store the mapped characters and provide for additional processing.

There may be several problems with such PDAs of the pπor art. For example, portability considerations may dictate that the PDA consume minimal electrical power and be of less weight. Due to the comprehensive functions a PDA may be designed to perform, meeting these requirements generally results in an increased designing and manufacturing costs. In addition, a paper trail may be mandated by law, and a scheme using a PDA to capture writings may not provide such paper trail.

Digitizers based scheme is another known scheme for electronically capturing writing. This scheme may not have power constraint problems but can have other problems as will be clearer from the following description. A digitizer generally comprises a digitizing surface and a pen. To write information, a pen may be moved while being pressed on a digitizer. In response to such movement, the digitizer generates data representing the movement, and provides the generated data to a computer. The data generated by the tablet may comprise X, Y coordinates corresponding to the movement of the pen. The X, Y coordinate data is immediately provided to a computer which processes the X, Y coordinate data and displays the writing.

One problem with the digitizers scheme is that such digitizers may not operate in the absence of a computer system as such digitizers draw power from the computer system. In addition, the digitizers may transfer data to computer systems immediately after a tablet generates the data. The digitizers therefore may not operate as stand-alone units. Such digitizers may accordingly be unsuitable for portable applications.

Therefore, what is needed is an electronic handwriting capture device which consumes minimal power and meets others portability and legal requirements.

SUMMARY OF THE INVENTION

The present invention is directed to a method and apparatus for electronically capturing and storing data representative of a pattern written by a user. A handwriting capture device in accordance with the present invention includes a digitizer surface on which a user can write a pattern. The digitizer generates a set of signal data representative of the pattern written by the user. The device of the present invention further includes a non- volatile memory storage for permanently storing the set of signal data. The set of signal data can be provided at a later convenient time to an external system (e.g., computer characters represented by the pattern.

The hand-writing capture device further includes a micro-controller, which receives the set of signal data from the digitizer and stores the received data in the non-volatile memory storage. An interface transfers the set of signal data to a computer system for further processing at a later time. The set of signal data in one embodiment compπse X, Y coordinate data corresponding to the movement of the pen in relation to the surface.

As the handwriting capture device of the present invention includes a non- volatile memory for permanently storing the X, Y coordinate data, the handwπting capture device may operate as a standalone device without requiring the presence of a computer system. In addition, as the interface transfers the data for later processing by a computer system, the handwπting capture device enables further processing such as character recognition by the computer system. Also, as the handwπting capture device need not perform complex functions such as character recognition, the design and manufacturing of the device is simplified.

In one embodiment, the handwπting capture device enables the user to store the set of signal data as logical pages, as would generally be organized while wπting on paper. For faster access, techniques such as indexing into the pages are used.

To rnimrnize the amount of storage required for stoπng a page in the non-volatile memory, the signal data representative of the patterns wπtten is stored in a compressed format.

Further features and advantages of the mvention, as v/ell as the structure and operation of vaπous embodiments of the invention, are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the correspondmg reference number.

Brief Descπption of the Drawings The present mvention will be descπbed with reference to the accompanying drawings, wherein FIG. 1 A is a block diagram providing an overview of the operation of the handwriting capture and storage device in accordance with the present mvention; FIG. IB is a diagram of an embodiment of the handwπting capture and storage device m one embodiment of the present invention including a HWSIM (Handwπting Storage and Indexmg Module), a digitizer, and a digitizer controller;

FIG. 1C is a block diagram illustrating the connections between the components of handwπtmg capture and storage device m one embodiment of the present mvention; FIG. 2 is a block diagram of HWSIM illustrating further details thereof m one embodiment of the present mvention;

FIG. 3 is a block diagram showing the logical organization of X, Y coordmate data m a memory module m one organization scheme;

FIG. 4 is a block diagram illustrating further details of page operations module in one embodiment;

FIG. 5 is a block diagram of an embodiment of the handwπtmg capture and storage device m a stationary setting such as a class-room or a library; and

FIG. 6 is a block diagram of an embodiment of the handwπtmg storage and capture device implemented as a portfolio for portability. DETAILED DESCRIPTION OF THE INVENTION

1. Overview and Discussion of the Invention

The present mvention is described in the context of handwπting capture and storage device (HCSD) 100 shown with another HCSD 190 and computer system 140 m FIG. 1 A. HCSD 190 can be 5 made and used similar to HCSD 100. Accordmgly, the descπption below with respect to HCSD 100 is applicable to HCSD 190 as well. HCSD 100 is shown connected to computer system 140 and HCSD 190 using signal lines/buses 104 and 109 respectively. The dotted connections 104 and 109 represent that HCSD 100 can operate as a stand-alone unit, but is capable of transferring information to computer system 140 and HCSD 190 at a later convenient time

o HCSD 100 enables a user to wπte, and captures a set of signal data representative of the wπtten pattern m a non- volatile memory Typically, a user wπtes information with an instrument such as a pen or a pencil However, HCSD 100 can be designed to capture other means of wπting information as well. A non-volatile memory is preferably provided within HCSD 100. In the alternative, a memory storage mterface such as one compliant with PCMCIA/Cardbus technology can be provided within 5 HCSD 100, and the mterface can be used to store the signal data in non-volatile memory modules available as removable cards. These non-volatile memory modules can be used with another HCSD 190 or computer system 140.

HCSD 100 can transfer the set of signal data to either computer system 140 or HCSD 190 over interface 105 at a later convenient time. HCSD 100 is preferably provided with a battery (or other 0 electrical power source) to operate as a stand-alone unit without requiring the presence of computer system 140.

Computer system 140 processes the received set of signal data to perform functions such as character recognition. That is, computer system maps the received signal data mto one or more of predetermined characters. Characters can mclude alpha-numeπc characters or other pre-determined 5 patterns of wntrng The implementation of computer system 140 needs to conform to the format in which HCSD 100 represents patterns and transfer the signal data. The word pattern, as used herein, can include several pages of information written by a user. The design and implementation of various formats and of HCSDs 100, 190 to capture writing in a corresponding format will be apparent to one skilled in the relevant arts by reading the disclosure provided herein. The implementation of computer system 140 to process signal data received in the corresponding format will also be apparent to one skilled in the relevant arts.

Even though interface 105 is shown as one block, it should be understood that interface 105 can in reality include multiple interface units. For example, one interface unit may be provided to communicate with HCSD 190, while another interface unit can be provided to communicate with computer system 140. Each interface can be implemented using different electrical and protocol standard as suited for the individual environments. The implementation of interface 105 will also be apparent to one skilled in the relevant arts based on the description provided herein.

In operation, a user writes a pattern using one of HCSDs 100 and 190. The pattern is captured, represented and stored as a set of signal data. A display unit 191 is optionally provided for the user to view information presently being written or that was stored a priori. Upon a user request, HCSD 100 transfers signal data representative of a pattern to computer system 140 on line/bus 104. Computer system 140 processes the received signal data to perform functions such as character recognition. That is, computer system 140 determines the characters wπtten by the user.

Unlike a digitizer, HCSD 100 can be used for enabling character recognition as a stand-alone unit as HCSD 100 includes a non-volatile memory for storing data. As used in the present application, a non- volatile memory can be any memory which stores signal data for a time long enough (at least a few minutes at the minimum) to allow a user to transfer the data at a later convenient time.

In addition, as HCSD 100 does not by itself perform complex functions such as character recognition, the implementation of HCSD 100 is simplified. Therefore, unlike a PDA, HCSD 100 can be cost-effective and be manufactured to consume relatively lower amount of electrical power, making it further suitable for portable applications.

In addition, according to another aspect of the present mvention, HCSD 100 organizes the information stored as logical blocks, each block corresponding to units such as pages. Accordingly, a user may organize the information in pages as he or she would if he/she were writing on a paper.

Thus, the present invention is particularly suited for systems implemented for portability.

However, the present invention can be adapted for implementation m any system for capturing handwriting. The invention can be implemented in hardware, software, firmware or combination of the like. An example implementation of HCSD 100 will now be explamed in further detail.

2. Example Implementation of HCSD 100 FIGS. IB and 1C illustrate an example implementation of HCSD 100 of the present mvention.

FIG. 1 B is a block diagram illustrating an external view of the embodiment. FIG. 1 C is a block diagram illustrating the inter-connection and operation of logical sub-blocks of the embodiment. In the drawings, like elements are referred to by similar numbers.

With reference to FIG. IB, there is shown pen 165 on top of the surface of digitizer 170. Paper 107 is optional . If a paper trail is not required, a user can wπte directly on digitizer 170. Also, the paper placed on the digitizer may be a form filled by usmg HCSD 100. The information filled usmg the form may be used for further processing at a later time.

Digitizer 170 records movement of pen 165 on the surface of digitizer 170 as a set of signal data.

The signal data preferably includes X, Y coordinates, with each coordmate pair representing a pomt the movement path of pen 165. Hardware storage and mdexmg module (HWSIM) 120 stores the signal data in a non- volatile memory, and transfers the stored data to computer system 140 for later processmg.

FIG. 1C illustrates the logical connections between some of the components described m FIG IB. In addition, HWSIM 120 is shown to mclude micro-controller 121, memory interface 122. and non-volatile memory 123. Micro-controller 121 interfaces with digitizer controller 110 to receive signal data representative of a pattern wπtten by a user. As already noted, a pattern can mclude one or more characters. Micro-controller 121 interfaces with memory mterface 122 to store the signal data m nonvolatile memory 123. In addition, micro-controller 121 stores the signal data as logical blocks, with each block correspondmg to a unit such as a page

Continuing the descπption of HCSD 100 with reference to FIGS 1 B and 1 C, digitizer 170 can be conventional and one of several products available m the market can be used for digitizer 170 A user wπtes a pattern by impressmg pressure on the surface (or a paper on the surface) of digitizer 170 usmg pen 165 Digitizer 170 may determine whether pen 165 is up or down, and generate X-Y coordmate data to mdicate the location of pen 165 on the surface of digitizer 170

However, digitizer 170 may be capable of otherwise sensmg movement of pen 165 or other ob_ject in a pattern correspondmg to the information For example, digitizer 170 may be capable of sensmg visually the movement of pen 165 It is therefore within the scope and sprπt of the present mvention to use other means for capturing information As used in the present application, a pattern typically compπses alpha-numeπc characters generally used by people to wπte information However, a pattern can mclude any pattern which can be mapped mto or associated with a pre-specified character/symbol

Digitizer 170 generates X, Y coordmates to mdicate location of pen 165 In a preferred embodiment, the X, Y coordmates corresponds to a physical location on the surface of digitizer 170 In an alternative embodiment, the X, Y coordmates may correspond to a position on a logical surface Such a logical surface may have dimensions larger or smaller than the physical surface of digitizer 170 Pπor art techniques such as scroll bars may be used to map such a logical surface to physical surface of digitizer 170

Digitizer controller 110 provides an mterface to transfer X, Y coordmate data from digitizer 170 to micro-controller 121 of HWSIM 120 Micro-controller 121 receives data correspondmg to X. Y coordmates. and stores the received data m non- volatile memory 123 To minimize the amount of storage space required m non- volatile memory 123, HWSEVl 120 may reduce the amount of data to be stored. Examples of such reduction schemes will be descπbed m further detail below with reference to an example implementation of HWSIM 120.

As micro-controller 121 stores the data m a non- volatile memory, the data may be later transferred to computer system 140 for further processmg. The throughput performance of HWSIM 120 may be enhanced by employing a random accessible memory (as opposed to accessmg usmg a traditional hard-dπve).

Also, memory mterface 122 can be designed to operate with removable memory modules such as those implemented usmg PCMCIA/ Cardbus standards known well m the relevant arts Accordmgly, in one embodiment, memory mterface 122 compπses a PCMCIA mterface Users can plug-m PCMCIA cards mto HCSD 100, and remove the cards after wπting (and consequently capturing) the information

Micro-controller 121 transfers the X, Y coordmate data from HWSIM 120 to computer 140 usmg communication path 104 Communication path 104 may be provided through mterface 105 as noted above. The transfer may be accomplished by usmg any of the protocols such as RS-232 It will be appreciated that other types of protocols and hardware may be used to transfer the data without departing from the scope and sprπt of the present invention

Micro-controller 121 further maintains information relating to organization of the information mto different pages. In other words, as a user wπtes information on the surface of digitizer 170. the user may specify a page-break, and HWSIM 120 maintains such page-break information HWSIM 120 may automatically generate a page-break (soft page-break) if the amount of information wπtten exceeds a page. The organization of pages and the details of HWSIM 120 facilitating a user to control such organization will be explained m further detail below

From the above, it will be appreciated that HCSD 100 of the present mvention may operate as a stand-alone device without requiring the presence of computer system 140 As the X, Y coordmate data is permanently stored m a non- volatile randomly accessible memory, the data may be later transferred to computer system 140 at a user's option In addition, a user may optionally wπte on paper pad 107, and cause the information to be automatically captured m HWSIM 120. An example implementation of HWSIM 120 will be explamed m further detail below.

3. Example Implementation of HWSIM 120

FIG.2 is a block diagram illustrating an example implementation of HWSIM 120. HWSIM 120 comprises memory mterface 122, non- volatile memory 123 , mput mterface 210, micro-controller 121, page operations controller 203, and status indicators 202, 204, and 205. HWSIM 120 further mcludes a power circuit including power supply 230, power status mdicator 202, device status circuit 220. Each component will be explamed m further detail below.

Input mterface 210 receives X, Y coordmate data from digitizer 170 under the control of digitizer controller 110 and micro-controller 121. The electπcal and functional characteπstics of mput mterface 210 may need to be consistent with those of digitizer controller 110. While mput mterface 210 receives the data, micro-controller 121 places status mdicator 204 m an ON state to mdicate that HCSD

100 is receivmg data.

Micro-controller 121 receives X, Y coordmate data from mput mterface 210, and stores the received data m non- volatile memory 123 as noted above To minimize the size of memory m memory storage 207, in one embodiment of the present mvention, micro-controller 121 employs two techniques, one for data reduction and the other for data compression. Both are explamed below.

During the data reduction phase, micro-controller 121 determines whether each of the X-Y coordmates need to be stored. For example, some tablets may transmit X-Y coordmate data even for pen-up positions, i.e., when pen 165 is not touchmg surface of digitizer 170. HCSD 100 may not need such X-Y coordmate data correspondmg to pen-up positions for handwπting recognition. Accordmgly, micro-controller 121 may ignore X-Y coordmate data correspondmg to pen-up positions

Micro-controller 121 may further ignore X-Y coordmate data which may not be required to display characters on computer system 140 with a given display resolution. For example, the resolution of X-Y coordmates captured by digitizer 170 is usually much higher than what is needed for displaying on a screen of computer system 140. In one embodiment, the resolution of digitizer surface may have a resolution of four times the resolution of a computer display screen After storing X-Y coordmates of a point, micro-controller 121 computes an area (for example, a circle) around the stored pomt If a following pomt falls within the area, micro-controller 121 may ignore such a following pomt

After determining which X-Y coordmates to store, micro-controller 121 may compress the X-Y coordmate data for further reducmg the amount of memory space required m memory storage 207. In one embodiment, micro-controller 121 may compπse a semiconductor chip such as Intel 8051 available from Intel Corporation, 2200 Mission College Blvd., Santa Clara, CA 95052

As to data compression, micro-controller 121 can use one of several well-known schemes for compressmg X, Y coordmate data While compressmg X, Y coordmate data, micro-controller 121 takes advantage of a high correlation generally present between X-Y coordmates of adjacent points of a writing. One embodiment uses vector based compression m which vector differences (e.g , difference between X-coordinates of successive points) are computed, and stores only the vector differences By usmg such a vector differences, micro-controller 121 of one embodiment may compress 16 bits of vector data mto 5 bits.

To transfer the X, Y coordmate data to computer system 140, micro-controller 121 retπeves the compressed data from memory storage 207, decompresses the compressed data to generate X. Y coordmate data, and sends the X, Y coordmate data to computer system 140 As will be appreciated, depending on compression/ decompression scheme chosen, the X. Y coordmate generated by decompression may vary m mmor respect from X, Y coordmate data compressed While transfemng X, Y coordmate data to computer system 140, micro-controller 121 may place status mdicator 205 m an ON status to mdicate that data is bemg transferred out of HCSD 100

Page operations controller 203 allows a user to logically separate the information wπtten mto pages as may be commonly done while wπting directly on paper Page operations controller 203 further enables a user to move among different pages or lmes m the information wπtten. In one embodiment. the navigation is sequential, that is, a user may access only an immediately following or precedmg page from a given page The organization of information mto pages and the manner m which a user can control the organization will be explamed m further detail below with reference to FIGS 3 and 4

Power supply 230 generates the power needed for vaπous elements of HCSD 100 Power supply 230 may generate such power from either a battery or other types of power sources Status indicator 202 mdicates whether power supply 230 has sufficient power to dπve HCSD 100 Device status circuit 220 determines any malfunctioning conditions which may be drawing unneeded power from power supply 230, and generates an alarm The alarm causes switch 232 to shut-off power dissipation The implementation of such a power control circuit will be apparent to one skilled m the relevant arts based on the descπption provided herein

The descπption of other aspects of the present invention will now be continued with reference to FIGS 3 and 4 below

4. Logical Organization in Non-Volatile Memory

FIG 4 shows one way m which memory controller 122 organizes m non- volatile memory 123 data signals representative of a pattern The data signals need to be generally organized to allow for easy navigation and to provide for msertion of text In one embodiment, memory 123 is organized as fixed -size blocks 410, 415, 425 and 430 Each block is typically used to store data signals representative of a page

The first block 410 mcludes pomters to active pages Thus, pomters 411 and 412 pomt to pages stored starting m blocks 415 and 425 respectively To facilitate addition (or msertion) or additional data to a pre-existing page, pomters are provided at the end of each block 410, 415, 425 and 430 For example, block 415 mcludes pomter 421, which pomts to block 430 Thus, when block 415 is full storing data correspondmg to a page, block 430 is used to continue to store additional data

Thus, usmg a scheme such as the one descπbed above, micro-controller 121 stores data correspondmg to each page m a block If more than one block is required to store data correspondmg to a page, a pomter is provided at the end of the first block, which pomts to a new block Typically, pages with dense writing require additional blocks to store the signal data.

The same scheme permits additional data to be added to a page also without having to copy data corresponding to the page to new locations of memory 123. That is, if a user adds information in the middle of a pre-existing page, only the block corresponding to the pre-existing page will be modified. If data corresponding to the resulting new page does not fit into one block, the pointer scheme explained above can be used to use a new block to store the new page.

Thus, micro-controller 121 stores signal data representative of a writing in non- volatile memory 123 according to the example scheme shown above. By using pointers such as those in first area 410, micro-controller 121 can store data representing several pages non- volatile memory 123. According to another aspect of the present invention, HCSD 100 provides a user the ability to navigate through the different pages stored in the non-volatile memory 123. One arrangement by which such navigation is allowed is explained below with reference to page operations controller

5. Navigation Control

FIG. 3 is a block diagram showmg different buttons 301 , 302, 306, 307, 308, 309, and 310 for navigating through the information stored non-volatile memory 123, and the status indicators 303 and 305 to display different status information of interest. The buttons and status indicators can be designed integral to HWSEVI 120, and specifically be controlled by micro-controller 121. The buttons enable a user to navigate through the information stored in non-volatile memory 123, and view the accessed information on display screen 191.

The status indicators include a page number indicator 303 for displaying a number of the page presently being displayed. In one embodiment, page number indicator 303 is implemented as a three digit register indicating a current page number. The remaining pages counter 305 provides an indication of the number of unused fixed size blocks remaining in non-volatile memory 123. As each block typically stores a page (of writing), counter 305 provides an indication of the number of additional pages that a user can write. The buttons provided mclude next page button 301 , previous page button 302, hard page break insert key 310, page break delete key 306, cursor movement keys 307 and 308, and lme delete key 309

Next page button 301 and previous page button 302 are used by a user navigate across different pages

^* Cursor movement keys 307 and 308 are used to move cursor to a next lme or previous lme respectively Line delete key 309 can be used to delete information correspondmg to a lme on a display.

Micro-controller 121 (shown m FIG.2) operates m cooperation with page-operations controller buttons to support vaπous cursor movement operations and data deletion functions. A user may use video display 191 shown m FIG. 1 during cursor movement operations

From the above descπption, it should be understood that the HCSD 100 of the present mvention can be used for capturmg wπtings m the form of signal data The signal data can be later transferred to a computer system, which performs functions such as character recognition While capturmg the data, HCSD 100 enables a user to organize information as different pages A suitable memory organization is chosen to facilitate a user to wπte information

The mvention described above can be adapted for use in several environments. Some of such example environments will now be explamed

5. Present Invention Adapted for Use in Places Such as Libraries and Schools

FIG. 5 is a diagram of an embodiment of HCSD 100 of the present mvention, which is affixed to table 550. A screw-type attachment or any other attachment well-known m the art may be used to permanently affix HCSD 100 to desk-top 550. HCSD 100 mcludes PCMCIA slot 510 for receivmg a PCMCIA card 520. PCMCIA slot 510 typically mcludes memory mterface 122 and PCMCIA card 520 corresponds 520 to non- volatile memory 123.

As a user wπtes on a surface of digitizer 170 (or alternatively on a paper placed on digitizer

170), PCMCIA slot 510 and the associated circuitry stores X, Y coordmate data correspondmg to the information wπtten m PCMCIA card 520. PCMCIA card 520 may be detached from HCSD 100, and be replaced with another PCMCIA card 520 The information stored m PCMCIA card 520 may be sent later to computer system 140 for further processing. Alternatively, a user may remove PCMCIA card 520 after storing the information, and use the removed card with another computer system 150.

Such HCSD 100 may be provided in places such as libraries and schools. Users can use their own PCMCIA card 520 for storing information, and take the card with them for further processing. Although the present embodiment is described in the context of PCMCIA standard technology, it will be appreciated that a different type of memory module may be used with a compatible interface without departing from the scope and spirit of the present invention.

6. HCSD Provided as a Portfolio for Portability

FIG. 6 is a diagram showing an embodiment of HCSD 100 packaged as a portfolio 600. Portfolio 600 consists of digitizer 170, pen 165 , display 191. and the HWSIM 120. The operation of digitizer 170, pen 165 and display 191 has been explained above. In addition, portfolio 600 consists of a battery pouch 610 for storing additional batteries and other attachments. As will be readily appreciated, portfolio 600 is particularly adapted for portability.

7. Conclusion While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

What is claimed is: 1. A handwriting storage and capture device, which in combination with another digital processing system enables handwriting capture and recognition, the handwriting storage and capture device comprising: a digitizer comprising a surface, wherein a user can write a pattern on the surface, the digitizer generating a set of signal data representative of the pattern, the pattern representing one or more characters; a memory interface for storing the set of signal data in a non- volatile memory; a micro-controller coupled to the digitizer and the non-volatile memory, the micro-controller receiving the set of signal data from the digitizer and storing the set of signal data in the non- volatile memory; and an interface coupled to the non- volatile memory, the interface designed to transfer the set of signal data stored in the non- volatile memory to the digital processing system, wherein the digital processing system processes the signal data to recognize the characters represented by the pattern.

2. The device of claim 1, wherein the set of signal data comprises a set of X, Y coordinate data representing the movement of a pen relative to the surface of the digitizer when the user writes said pattern.

3. The device of claim 2, wherein the non- volatile memory comprises a PCMCIA card.

4. The device of claim 1 wherein the micro-controller maintains an index to organize the writing into a plurality of logical entities.

5. The device of claim 12, wherein the micro-controller divides the non-volatile memory into a plurality of blocks, wherein each block stores a page of the writing.

6. The device of claim 13 , wherein the micro-controller provides a pointer from a first block to a second block if a page does not fit into the first block, and wherein the micro-controller stores the page m the first block and the second block.

7. The device of claim 6, further comprising one or more navigation keys, which permit a user to move across different paged and lines.

8. The device of claim 2, wherein the interface is designed to transfer the set of signal data to another handwriting capture and storage device.

9. The device of claim 2, wherein the micro-controller stores X, Y coordinate data of a first position of the digitizer surface, and determmes whether or not to store X, Y coordmate data of a subsequent position if the subsequent position is within a predetermined distance of the first position.

10. The device of claim 2, wherein the micro-controller stores the X, Y coordmate data m a compressed format.

11. The device of claim 10, wherein the micro-controller computes difference of X-coordmates between successive points to be stored, and stores the difference in the non-volatile memory.

12 A portfolio, which m combination with another digital processmg system enables handw╧Çtmg capture and recognition, the portfolio comp╧Çsmg a digitizer comp╧Çsmg a surface, wherem a user can w╧Çte a pattem on the surface, the digitizer generating a set of signal data representative of the pattem, wherem the pattem mcludes one or more characters; a memory mterface for permanently storing the set of signal data in a non- volatile memory, a micro-controller coupled to the digitizer and the non-volatile memory, the micro-controller receiving the set of signal data from the digitizer and sto╧Çng the set of signal data m the non-volatile memory; an mterface coupled to the non-volatile memory, the mterface designed to transfer the set of signal data to the digital processing system, wherem the digital processmg system processes the signal data to recognize said one or more characters mcluded m the pattem; a power source operating from a battery; and a battery pouch for storing one or more batte╧Çes for the power source.

13. A handw╧Çting capture device, which m combination with another digital processmg system enables handw╧Çtmg capture and recognition, the device comp╧Çsmg a digitizer comp╧Çsmg a surface, wherem a user can w╧Çte a pattem on the surface, wherem the pattem mcludes one or more characters, the digitizer generating a set of signal data representative of the w╧Çting, wherem the set of signal data comp╧Çses a set of X, Y coordmate data representing the movement of a pen relative to the surface of the digitizer, a memory mterface for permanently sto╧Çng the set of signal data m a non-volatile memory, a micro-controller coupled to the digitizer and the non-volatile memory, the micro-controller receivmg the set of signal data from the digitizer and storing the set of signal data m the non-volatile memory, wherem the micro-controller stores X, Y coordmate data of a first position on the digitizer surface and determmes whether or not to store X, Y coordmate data of a subsequent position if the subsequent position is within a predetermmed distance of the first position, the micro-controller mamtammg an mdex to organize the w╧Çting mto a plurality of logical entities, the micro-controller logically dividing the non- volatile memory mto a plurality of blocks, wherem each block stores a page of the w╧Çting, the micro-controller providmg a pomter from a first block to a second block if a page does not fit mto the first block and wherem the micro-controller stores the page m the first block and the second block, and an mterface coupled to the non-volatile memory, the mterface designed to transfer the set of signal data to the digital processmg system, wherem the digital processmg system processes the signal data to recognize said one or more characters mcluded m the pattem

14 A device, which m combination with another digital processmg system enables handw╧Çting capture and recognition, said device comp╧Çsmg means for generating a set of signal data representative of a pattem correspondmg to a set of characters w╧Çtten by said user, means for permanently sto╧Çng said set of signal data m a non-volatile memory, and means for transfemng said set of signal data to a digital processmg system at a later time, wherem said another digital processmg system processes said set of signal data to generate said set of characters.

15 A method of electronically capturmg and recognizing characters w╧Çtten by a user, said method comp╧Çsmg the steps of: generating a set of signal data representative of a pattem representing a set of characters, the pattem bemg w╧Çtten by said user on a digitizer surface of a handwnting storage and capture device, permanently sto╧Çng said set of signal data m a non- volatile memory of said handw╧Çtmg storage and capture device; and transfemng said set of signal data to a digital processmg system at a later time, wherem said digital processmg system processes said set of signal data to recognize said set of characters

16 The method of claim 15, wherem the step of permanently sto╧Çng further comp╧Çses the steps Of compressmg the set of signal data; and sto╧Çng the data resulting from said step of compressmg m said non- volatile memory

17 The method of claim 15, wherem the set of signal data comp╧Çse X, Y coordmate data representative of movement of a pen relative to said digitizer surface, and wherem said step of compressmg comp╧Çses the step of sto╧Çng X, Y coordmate data of a first position of the digitizer surface; and sto╧Çng X, Y coordmate data of a subsequent position only if the subsequent position is not within a predetermmed distance of the first position

18 The method of claim 15, wherem the step of compressmg comp╧Çses the step of computing the difference of X, Y coordmates between successive pomts to be stored, and sto╧Çng the difference m the non-volatile memory

19. The method of claim 15, further comprising the steps of: dividing the non-volatile memory into a plurality of blocks, wherein each block is designed to store signal data of a page; and storing another pointer in one of said plurality of blocks if a given page does not fit in said one of said plurality of blocks, said another pointer pointing to another one of said plurality of blocks, wherein said one of said plurality of blocks and said another one of said plurality of blocks together store the given page.